See
the recipe at Mango custard cake ( double the amount for all ingredients as we need two
layers of cake )

For
custard:

4 cups
milk

½
cup vanilla custard powder

1 cup
sugar

½
tsp cardamom powder

For
jelly:

1
packet of mango jelly

Method:

Prepare
the cake as per the recipe. Let it cool down on rack. Mean time start
preparing the custard.

Take 3
cup of milk. Keep it on boil. In another one cup of cold milk
dissolve vanilla custard powder.

After
two boils add this custard milk to the boiling milk.

Keep
stirring it continuously. And scrap the walls of your pan. It will go
thick. Keep stirring it for around 5 to 7 minutes now add sugar and
cardamom powder. Mix for another 2 minutes. And keep it under fan to
cool down for 15 to 20 minutes. It should cool down between room
temperature and warm.

Now
assembling part. Cut the cake into two parts. So you have two layers.
Keep back the first layer of your cake into the baking dish. Pour
half of your custard. Now place the second layer of cake. Pour rest
of the custard on cake.

Keep
it in refrigerator for 2 hours.

Now
dissolve jelly as per the instructions. Pour the jelly on top of the
custard. Decorate it with fruits of your choice or chocolate.